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✉️ Email Delivery

Documentation, reference material and tutorials for CRM-NG SMTP Email: setup guides for every mail service, troubleshooting, and one article per error message.

Error: Unauthorized: key not found (Brevo)

Updated

By Duane GarnerChief Executive Officer (CEO)
Summarize: Claude ChatGPT View Markdown
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Brevo cannot find the API key the plugin sent. It was deleted, mistyped, or is an SMTP key rather than a v3 API key.

This article is for sites using the Brevo mailer where a send fails with "Key not found".

The error as you see it

Unauthorized: Key not found

Shown by the Brevo mailer, in the failed-send banner, in Tools → Debug Events and in the Email Log. Brevo returns it with HTTP status 401.

What this error means

The plugin sends each email to Brevo's API with your API Key. Brevo looked for that key among the account's API keys and found nothing. Unlike the IP-related "Unauthorized" error, the problem here is the key itself.

Common causes

  • An SMTP key was pasted instead of an API key. Brevo makes two kinds of keys on the same page. SMTP keys start with xsmtpsib- and work only for SMTP sign-in. The Brevo mailer needs a v3 API key, which starts with xkeysib-.
  • The key was deleted in Brevo.
  • The key was copied incompletely, or with a leading or trailing space.
  • The key belongs to another Brevo account, for example a client's account when you meant your own.
  • A CRMNG_SMTP_* constant in wp-config.php still holds an old key.

How to fix

  1. Open Brevo's keys page

    Sign in to https://app.brevo.com/, open the account menu at the top right, and choose SMTP & API. Select the API Keys tab (not the SMTP tab).

  2. Check the existing key

    If the key your site uses is missing from the list, it was deleted. Brevo shows only part of each key after creation, so you cannot copy an old one again.

  3. Create a new API key

    Choose Generate a new API key, name it after your site, and copy the full key straight away. Check that it starts with xkeysib-.

  4. Save it in CRM-NG SMTP

    In CRM-NG SMTP → Settings → General, with Brevo selected, use Remove API Key, paste the key into API Key and press Save Settings.

  5. Check for constants

    If the field cannot be edited, the key is set in wp-config.php with a CRMNG_SMTP_* constant. Update it there.

  6. Send a test

    Go to CRM-NG SMTP → Tools → Email Test, fill in Send To and press Send Email.

Verify it worked

The test page shows "Test email sent successfully! Check your inbox to confirm delivery." The message also shows in Brevo's transactional email logs.

Notes

  • If you want to keep an SMTP key, use it only with the Other SMTP mailer (host and login are shown on Brevo's SMTP tab). The Brevo mailer is the better choice for most sites.
  • Delete keys you no longer use, so a leaked old key cannot be misused.
  • If the error mentions an IP address or verification instead, see Unauthorized: not verified or IP not authorized.
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